The present invention relates to a unleaded aviation gasoline composition, its production and its use in a reciprocating spark ignition aircraft engines.
The majority of aviation gas today is unleaded, especially within Europe, but there are still blends for reciprocating spark ignition aircraft engines mainly in America which use leaded fuels in order to increase the octane number. Due to the huge environmental impact of lead there is a strong need for substitution and replacement within non-leaded additives.
As published in Industrial and Engineering Chemistry, 1955, Vol 47, No. 10 pages 2141-2146 “by J. E. Brown et al several amine-containing additives had been tested in anti-knocking analysis, including N-methyl-p-toluidine and N-methyl-m-toluidine.
Several other US-patents disclose the use of at least one aromatic amine, such as U.S. Pat. Nos. 5,470,358 B, 6,258,134 B, 6,767,372 B and 7,897,034 B2 as well as in U.S. Pat. No. 8,628,594.
Some of the most effective anti-knocking agents have a negative impact on the freezing point which is defined in ASTM D 2386-06 and therefore not useful as an aviation fuel.
As best understood, none of the references discloses compositions free of lead and having both a sufficiently low freezing point and a high octane number (effective for unleaded aviation gasoline) and, moreover, which compositions also ensure large scale commercial availability for reasonable prices.
It was therefore an object of the present invention to provide a highly effective high octane unleaded aviation gasoline composition which also fulfills the criteria of a freezing point lower than −58° C.